Effects of hormonal replacement treatment on bone mineral density and metabolism in hypogonadal patients.

We investigated 22 male patients affected by prepubertal hypogonadism with a mean age of 34.3+/-5.2. A significant reduction of bone mineral density (BMD) at both the lumbar spine (L2-L4, -14%, 1.039+/-0.11 vs. 1.217+/-0.16 g/cm(2), P=0.005) and femoral neck (-11%; 0.927+/-0.09 vs. 1.034+/-0.16 g/cm(2), P=0.01) was found in patients compared to age-matched controls. The mean Z score was -1. 55 for vertebrae and -1.33 for femur. Eleven and nine patients, respectively, had a lumbar and femoral BMD at least 1 S.D. below the normal mean; 8 and 4, respectively, 2 S.D. below. There was a strong positive correlation between BMD and duration of hormone replacement treatment (HRT) for both sites: respectively, r=0.71, P<0.005 for the vertebrae, and r=0.60, P<0.01 for the femur. A weak correlation was also present between onset of HRT and BMD: r=0.6, P<0.01 at the lumbar level, and r=0.47, P<0.05 at the femoral neck.